In the Linux kernel, the following vulnerability has been resolved: fuse-uring: Avoid use-after-free in fuse_uring_async_stop_queues fuse_uring_async_stop_queues() might run when the last reference on ring->queue_refs was already dropped. In order to avoid an early destruction a reference on struct fuse_conn is now taken before starting fuse_uring_async_stop_queues() and that reference is only released when that delayed work queue terminates.
Casky was already ahead
This CVE exploits attack patterns that Casky's 0matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.
CVE-2026-64261 is a use-after-free vulnerability in the Linux kernel's fuse-uring subsystem, specifically within the fuse_uring_async_stop_queues() function. This vulnerability occurs when the function executes after the last reference to ring->queue_refs has been released, potentially leading to access of already-freed memory. Linux kernel vulnerabilities of this nature are critical because the kernel runs at the highest privilege level and affects all systems using vulnerable versions. This impacts any Linux system relying on FUSE (Filesystem in Userspace) with uring support enabled, making it a concern for cloud infrastructure, container platforms, and general-purpose Linux deployments where privilege escalation or denial of service could have severe consequences.
While CVE-2026-64261 has no mapped MITRE ATT&CK techniques or associated Casky skills in the current dataset, practitioners would detect exploitation attempts through memory safety violations and kernel panic signatures. Detection would focus on observing abnormal process termination, kernel oops messages related to fuse operations, or unexpected system crashes following fuse-uring interaction patterns. Extended reasoning analysis would correlate system-level indicators such as reference counting anomalies in kernel structures, delayed work queue execution timing inconsistencies, and memory access violations. Security teams should monitor kernel logs for fuse-uring stack traces and implement kernel version inventory controls to identify and patch affected systems before attackers can trigger the use-after-free condition through carefully crafted FUSE filesystem operations.
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